1. (A) The microbiome field has exploded in recent years.
(A) The microbiome field has exploded in recent years. This graph shows the number of publications per year since the first appearance in 2002 of the term “microbiome.” (Source: ISI web of knowledge [ *, numbers for 2017 represent data from the period up to 4 December. (B) Invertebrate microbiomes are simpler than vertebrate microbiomes. These box plots show the numbers of unique tag sequences detected in samples of various categories. Categories were defined by the Earth Microbiome Project ( which used a Deblur reference-free method of clustering sequences (15). In this data set of hundreds of samples, there is a clear trend toward simpler microbiomes in invertebrates containing fewer microbial sequences per individual. Intriguingly, the surfaces of vertebrate animals (right panel) and invertebrate animals (left panel) mostly appear to host similar numbers of different microbes. Despite the massive sampling effort of this extensive survey, there are differences in sampling methods and efforts between studies of vertebrates and invertebrates and a bias toward particular phylogenetic groups in both categories (see Fig. S2). Numbers in brackets indicate the number of samples in each category.
Jillian M. Petersen, and Jay Osvatic mSystems 2018; doi: /mSystems